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TROPICAL STORM DALILA DISCUSSION NUMBER  23
NATIONAL WEATHER SERVICE MIAMI FL
8 AM PDT THU JUL 26 2001

DALILA HAS SHOW ANOTHER CONVECTIVE FLARE-UP SOUTHWEST OF THE CENTER
OVER THE PAST FEW HOURS...BUT TOPS ARE NOW WARMING.  OVERALL...THE
CYCLONE IS NOT QUITE AS IMPRESSIVE AS 24 HR AGO.  SATELLITE
INTENSITY ESTIMATES ARE 65 KT...55 KT...AND 45 KT FROM TAFB...SAB...
AND AFWA RESPECTIVELY.  BASED ON THIS THE MAXIMUM WINDS ARE LOWERED
SLIGHTLY TO 55 KT.

THE INITIAL MOTION IS 290/5.  THE SYNOPTIC PATTERN DISCUSSION IS
PROBABLY STARTING TO SOUND LIKE A BROKEN RECORD...AS DALILA REMAINS
SOUTH OF THE LOW/MID LEVEL SUBTROPICAL RIDGE WITH A MID/UPPER
TROUGH OVER THE SOUTHWESTERN U.S.  LARGE-SCALE MODELS FORECAST THE
TROUGH TO LIFT OUT AND THE RIDGE TO SOMEWHAT STRENGTHEN.  THIS
SHOULD CONTINUE DALILA ON A WEST-NORTHWEST TO WEST TRACK.  GIVEN
THAT THIS SCENARIO LOOKS PRETTY STRAIGHT FORWARD...NHC HURRICANE
GUIDANCE SHOW A REMARKABLY LARGE SPREAD.  THE AVN SHOWS A SLOW
WESTWARD MOTION...WHILE THE GFDL SHOWS A SLOW NORTHWEST MOTION.  THE
BAMS AND NHC91E SHOW A MUCH FASTER WESTERLY MOTION...WHILE BAMD AND
LBAR SHOW A MUCH FASTER WEST-NORTHWEST MOTION.  SINCE FAST AND
NORTHWEST FORECASTS HAVE NOT BEEN VERIFYING FOR THE PAST FEW
DAYS...THE OFFICIAL FORECAST WILL BE AN UPDATE OF THE PREVIOUS SLOW
MOTION IN BEST AGREEMENT WITH CLIPER.
 
WHILE THE CENTER IS STILL OVER 26C SEA SURFACE TEMPERATURES...
WATER VAPOR IMAGERY AND SATELLITE CLOUD WINDS FROM CIMSS SHOW AN
UPPER LEVEL EASTERLY SURGE APPROACHING DALILA.  THIS SUGGESTS THAT
VERTICAL SHEAR MAY INCREASE SOMEWHAT DURING THE NEXT 24 HR...AND
THIS IS REFLECTED IN SHIPS GUIDANCE.  WHILE THE SURGE MAY DIMINISH
AFTER 24 HR...BY THAT TIME THE CYCLONE SHOULD BE OVER 25C WATER...
COOLING TO 23C BY 72 HR.  THE INTENSITY FORECAST WILL CALL FOR SLOW
WEAKENING DURING THE FIRST 24 HR...WITH A FASTER WEAKENING
THEREAFTER.  DALILA SHOULD BEGIN DISSIPATING BY 72 HR.  OF COURSE...
THAT IS WHAT THE FORECAST FROM YESTERDAY SAID.


 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     26/1500Z 19.9N 114.0W    55 KTS
12HR VT     27/0000Z 20.2N 114.8W    55 KTS
24HR VT     27/1200Z 20.5N 115.8W    50 KTS
36HR VT     28/0000Z 20.9N 117.1W    45 KTS
48HR VT     28/1200Z 21.3N 118.7W    35 KTS
72HR VT     29/1200Z 21.5N 121.5W    25 KTS...DISSIPATING
 
 
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